Ethnicity is a primary sense of belonging to an ethnic group. Ethnic group is consanguine in nature, meaning, the ties are reckoned by blood and traced through the family tree. Thus, ethnicity refers to the household member's identity, by blood and not by choice nor by adoption/confirmation for any ethnic group, primarily the Indigenous Peoples (IPs).
Generally, ethnic grouping denotes genealogical and paternal lineage to any of the Philippines' group of native population. However, for the purpose of census, ethnic grouping also includes maternal lineage. As such, anybody whose consanguinity with either both parents or any one of them who is a member of an IP group, is an Indigenous Person.
The updated categories of ethnicity are provided by the National Commission on Indigenous Peoples and the National Commission on Muslim Filipinos.